| uk.abstract.en | Aim:
The aim of the study was to analyze the results of semiquantitative assessment of dopamine transporters scintigraphy n(DAT-SPECT) in patients with Parkinson's disease (PD) before initiating pharmacological treatment. Assess the dependence of measured parameters on age, define threshold diagnostic values, analyze correlation with the degree of clinical symptoms expression, and compare the values obtained from the commercial program DaTQUANT (GE Healthcare) and the academic tool BasGan (Italian Society of Nuclear Medicine).
Subjects and Methods:
This is a sub-analysis within a prospective longitudinal observational non-interventional study focused on comprehensive collection of clinical parameters in patients in the early stage of PD - the BIO-PD project. The group included 125 patients (mean age 60.4 ± 12.5 years, 78 males) with PD diagnosed by a specialist with clinical expertise in movement disorders diagnosis according to the criteria of the Movement Disorders Society before initiating pharmacotherapy. Furthermore, a control group was created, including 22 patients (12 males, mean age 60.6 ± 12.3 years) who underwent DAT-SPECT examination without subsequent diagnosis of PD. All PD patients underwent a standardized extensive examination, including DAT-SPECT, which was evaluated in the DaTQUANT and BasGan programs. The output consisted of specific binding ratio (SBR) values in respective regions of interest (ROIs) of the basal ganglia and the Z-score value from the DaTQUANT program. Semiquantitative parameters were further statistically processed.
Results:
The SBR values (here specifically mentioned for DaTQUANT, ROI putamen) showed a weak negative correlation with age. In the age group younger than 60 years, the Spearman's correlation coefficient (ρ) was -0.26, while in older individuals, the correlation further weakened (ρ -0.02). The Z-score values positively correlated with age (ρ 0.47 in younger individuals), and the correlation was observed in older individuals in the ROI of posterior putamen only (ρ 0.44). The threshold values for the diagnosis of PD in our sample were influenced by age. According to the ROC curve analysis, the optimal use is the ROI from the posterior putamen with SBR values of 1.86 for individuals younger than 60 years and 1.46 for
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older patients. For Z-score values, the thresholds are -2.02 for younger individuals and -0.40 for older patients. These parameters generally achieve sensitivities and specificities of 99-100%. Except for tremor, SBR and Z-score weakly correlate with the severity of motor symptoms in PD. Regarding non-motor symptoms, a significant correlation is weakly observed only for hyposmia (SBR from caudate ρ 0.31). The results of semiquantitative evaluation of DAT-SPECT in DaTQUANT and BasGan programs strongly correlate. BasGan achieves slightly higher correlation with the degree of clinical symptoms expression.
Conclusion:
Semiquantitative parameters of DAT-SPECT are particularly useful in the early stages of Parkinson's disease for diagnosis and correlation analyses. However, their interpretation requires caution and, importantly, consideration of the patient's age. In patients over 60 years old, the relative rate of radiotracer accumulation decline on DAT-SPECT is lower, and therefore, the definition of threshold diagnostic values needs to be adjusted accordingly.
Keywords:
Parkinson´s syndrome, Parkinson´s disease, DAT-SPECT, dopamine transporter scintigraphy, ioflupane. | cs |
